java生成pdf通过接口下载

pom

<dependency>
    <groupId>com.itextpdfgroupId>
    <artifactId>itextpdfartifactId>
    <version>5.5.11version>
dependency>

demo

package com.example.controller;

import com.itextpdf.text.*;
import com.itextpdf.text.pdf.PdfContentByte;
import com.itextpdf.text.pdf.PdfGState;
import com.itextpdf.text.pdf.PdfWriter;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.itextpdf.text.pdf.BaseFont;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.text.SimpleDateFormat;
import java.util.Date;

@RestController
@RequestMapping("pdf")
public class PdfController {
    @GetMapping("/createPdfDownload")
    public String createPdfToDownload(HttpServletResponse response) throws Exception {

        // 生成 pdf 名称
        Date date = new Date();
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String str = simpleDateFormat.format(date);
        String datetime = str.replace("-", "").replace(" ", "").replace(":","");
        String filename = "pdf_"+datetime+"_content.pdf";

        // 创建PDF
        Document document = new Document(PageSize.A4,60,60,15,40);
        try {
            // 设置响应头，控制浏览器下载该文件
            response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, "UTF-8"));
            //常用的有paragraph段落、phrase语句块、chunk最小单位块
            OutputStream out = response.getOutputStream();
            PdfWriter writer = PdfWriter.getInstance(document, out);

            // 打开文档
            document.open();
            BaseFont bfChinese = BaseFont.createFont("STSongStd-Light", "UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);
            for(int n = 0; n<2; n++){
                // 添加文字水印
                PdfContentByte cb = writer.getDirectContent();
                cb.beginText(); // 开始
                // 设置透明度
                PdfGState gs = new PdfGState();
                gs.setFillOpacity(0.2f);
                cb.setGState(gs);
                cb.setFontAndSize(bfChinese,100);
                cb.showTextAligned(Element.ALIGN_CENTER, "北京交通大学", 340, 410 , 60);
                cb.endText(); // 结束

                // 添加标题
                //通过Font去设置字体的基本属性：大小，加粗等等
                Font font  = new Font(bfChinese, 15, Font.NORMAL, BaseColor.BLACK);
                // 创建段落
                Paragraph title = new Paragraph("我是 title ", font);
                title.setAlignment(Element.ALIGN_CENTER);
                title.setSpacingBefore(40f);
                document.add(title);

                // 制作大文本数据
                StringBuilder stringBuilder = new StringBuilder();
                for (int i = 0; i <= 10; i++){
                    stringBuilder.append("如果说荷兰是橙色的，那阿姆斯特丹就是缤纷的彩色。");
                }
                Font font1  = new Font(bfChinese, 10, Font.NORMAL, BaseColor.BLACK);
                Paragraph context = new Paragraph(stringBuilder.toString(), font1);
                context.setFirstLineIndent(20);
                context.setLeading(12);
                context.setSpacingBefore(10f);
                document.add(context);

                // 开启新的一页
                document.newPage();
                //显示空内容的页
                writer.setPageEmpty(false);
            }
            // 关闭流
            document.close();
            writer.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        } catch (DocumentException e) {
            throw new RuntimeException(e);
        }
        return "ok";
    }
}